Package org.apache.lucene.codecs

Class PostingsWriterBase

java.lang.Object

org.apache.lucene.codecs.PostingsConsumer

org.apache.lucene.codecs.PostingsWriterBase

All Implemented Interfaces:

Closeable, AutoCloseable

Direct Known Subclasses:

Lucene41PostingsWriter

public abstract class PostingsWriterBase
extends PostingsConsumer
implements Closeable

Extension of PostingsConsumer to support pluggable term dictionaries.

This class contains additional hooks to interact with the provided term dictionaries such as BlockTreeTermsWriter. If you want to re-use an existing implementation and are only interested in customizing the format of the postings list, extend this class instead.

See Also:

• PostingsReaderBase

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	PostingsWriterBase()	Sole constructor.

Method Summary

Modifier and Type	Method	Description
abstract void	close()
abstract void	encodeTerm(long[] longs, DataOutput out, FieldInfo fieldInfo, BlockTermState state, boolean absolute)	Encode metadata as long[] and byte[].
abstract void	finishTerm(BlockTermState state)	Finishes the current term.
abstract void	init(IndexOutput termsOut)	Called once after startup, before any terms have been added.
abstract BlockTermState	newTermState()	Return a newly created empty TermState
abstract int	setField(FieldInfo fieldInfo)	Sets the current field for writing, and returns the fixed length of long[] metadata (which is fixed per field), called when the writing switches to another field.
abstract void	startTerm()	Start a new term.

Methods inherited from class org.apache.lucene.codecs.PostingsConsumer

addPosition, finishDoc, merge, startDoc

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

PostingsWriterBase

protected PostingsWriterBase()

Sole constructor. (For invocation by subclass constructors, typically implicit.)

Method Details

init

public abstract void init(IndexOutput termsOut)
                   throws IOException

Called once after startup, before any terms have been added. Implementations typically write a header to the provided termsOut.

Throws:

IOException

newTermState

public abstract BlockTermState newTermState()
                                     throws IOException

Return a newly created empty TermState

Throws:

IOException

startTerm

public abstract void startTerm()
                        throws IOException

Start a new term. Note that a matching call to finishTerm(BlockTermState) is done, only if the term has at least one document.

Throws:

IOException

finishTerm

public abstract void finishTerm(BlockTermState state)
                         throws IOException

Finishes the current term. The provided BlockTermState contains the term's summary statistics, and will holds metadata from PBF when returned

Throws:

IOException

encodeTerm

public abstract void encodeTerm(long[] longs,
 DataOutput out,
 FieldInfo fieldInfo,
 BlockTermState state,
 boolean absolute)
                         throws IOException

Encode metadata as long[] and byte[]. absolute controls whether current term is delta encoded according to latest term. Usually elements in longs are file pointers, so each one always increases when a new term is consumed. out is used to write generic bytes, which are not monotonic. NOTE: sometimes long[] might contain "don't care" values that are unused, e.g. the pointer to postings list may not be defined for some terms but is defined for others, if it is designed to inline some postings data in term dictionary. In this case, the postings writer should always use the last value, so that each element in metadata long[] remains monotonic.

Throws:

IOException

setField

public abstract int setField(FieldInfo fieldInfo)

Sets the current field for writing, and returns the fixed length of long[] metadata (which is fixed per field), called when the writing switches to another field.

close

public abstract void close()
                    throws IOException

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Closeable

Throws:

IOException